Lock stitch sewing machine



'May 23 1939- N. v. cHRlsTENsl-:N ET A1. 2,159,204

LOCK STITCH SEWING MACHINE Filed Jan. 25, 1956 .3 Sheets-Sheet l III llll

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May 23 1939- N. v. cHRlsTr-:NSEN m- Al. 2,159,204

LOCK STITCH SEWING MACHINE Filed Jan. 25, 1936 3 Sheets-Sheet 2 l?? lil-25? May 23 i939- N. v. cHRlsTENsEN ET AL 2,159,204

LOCK STITCH SEWING' MACHINE Filed Jan. 25, 1936 3 Shees-Slleei'I 3 my? am Patented May 23, 1939 UNITED STATES PATENT OFFICE .2,159,204 LocK STITCH SEWING MACHINE Application January 25, 1936, Serial No. 60,765

22 Claims.

This invention relates to lock stitch sewing machines, that is to say, to sewing machines wherein a rotary hook cooperates with a needle in .forming a series of lock stitches, the length of which is determined by intermittent progression of the fabric in the machine by a reciprocating feed dog.

The purpose of our invention is to reduce, as far as possible, friction and vibration in such machines so that they can be operated at much higher speeds than heretofore without undergoing derangement, and without heating up to a point where very rapid wear of the parts results.

As hereinafter more fully described we attain vthe foregoing objective by employing in a lock stitch sewing machine a number of relatively light parallel rotary shafts, one from which the needle is actuated, one carrying the rotary hook,

one from which the feed dog receives its feedv movements and still another from which lift movements are imparted to said feed dog; by mounting these several shafts in relatively short journals with liberal oil clearances around them; by driving said shafts through a system of intermeshing helical gears enclosed in a tight housing with a lubricant sump from which the oil is carried up through capillarity and by splash to lubricate the gear system as well as to lubrlcate contiguous bearings for the several shafts; and

by substitution of small diameter cranks and light connecting rods for the eccentrics and comparatively heavy eccentric straps heretofore generally employed to communicate reciprocating movements to the parts requiring it.

Other objects and attendant advantages will appear from the following detailed description of the attached drawings, wherein Fig. I is a front elevation of a lock stitch sewing machine con- -veniently embodying the present improvements,

40 portions of the machine frame being broken away and sectioned to expose important details which would otherwise be hidden.

Fig. II is a view, partly in plan and partly in section, looking as indicated by the arrows II-II 5 in Fig. I.

Fig. III is a vertical sectional' view taken as indicated by the arrows III-HI in Fig. I.

Figs. IV and V are transverse sectional views 50 taken as indicated by the arrows IV-IV and V-V in Fig. II; and

Fig. VI is a view corresponding to Fig. V showing a slightly modied form of feed mechanism. With more detailed reference first to Figs; I-V'I 55 of these illustrations, the sewing machine there shown comprises a flat bed plate or work support I, which is overhung by a hollow arm 2 reaching forwardly from an integrally formed hollow standard 3 at the rear end of said work support. J ournaled within the overhanging arm 2 is a longitudinal rotary shaft 4 which may be regarded as the main shaft of the machine, a'nd which at its protruding right hand end (Fig. I) is provided with a combined hand and belt wheel 5 so that the machine can be operated either manually or by power. Confined to vertical reciprocation in the head 6 at the forward end of the arm 2 is a bar I carrying the needle 8, said bar being l actuated by suitable means (not illustrated) on the shaft 4. A needle thread take-up, indicated at 9, is also operated by suitable means on the main shaft concealed within the head 6. En route from the take-up 9 to the needle 8, the thread is passed through a tensioning device at I0.

Cooperating with the needle 3 below the work support I is a rotary hook II which is secured to the forward end of a light rotary shaft I2 of small diameter extending longitudinally beneath said work support. Near its front end the shaft I2 is journaledrin a bushing I3 set into a pendant bracket lug l 5 of the work support I'. At its right hand end the shaft l2 is journaled in a bushing I6 set into the front wall of an oil sump I 'l formed as a hollow integral pendant projection of the bed plate I in direct communication with the hollow of the standard 3, said oil sump being closed at the bottom by a removable plate I8. The bushing I3, it will be particularly noted from Fig. I, affords a clearance I9 of substantial length about the shaft I2 for lubricating oil. The lubricant is introduced from above through a vertical hole 20 in the work support I and enters the clearance I9 by way of a registering lateral aperture 2| in the bushing I3. Also as shown, the oil hole 20 is intersected by a horizontal bore 22 which is packed with cotton or other fibrous absorbent material capable of holding a considerable quantity of reserve lubricant, the outer end of the bore being closed by a screw plug 24. The right hand bearing sleeve I6 for the hook shaft I 2 likewise affords a circumferential oil clearance 25 which is kept filled with splash oil from the reservoir Il, the oil entering said clearance by way of a port 26 open at the top of the inner end of said sleeve. The shaft I2 is held against axial displacement by a collar 21 and by the hub of a helical gear pinion 28 secured thereto at opposite ends thereof and respectively engaging the remote faces of the bearing sleeves I3 and I6 as shown in Fig. I.

The feed mechanism of the machine is located beneath the work support I and includes a feed dog 3D (Figs. II and IV) with toothed portions 3l operating in slots 32 of a throat plate33 made fast by screws 34 to the top of said work support. The feed dog 30 is secured, with provisions for vertical adjustment, to the front end of a feed bar 35 (Fig. IV), which, at its other end, has an apertured boss 36 wherein is secured a wrist pin 31. The opposite ends of this wrist pin 31 are engaged by spaced bosses 36 and 39 of a rocker 48 secured to a rock shaft 4I whereof the ends are in turn journaled in spaced pendant' lugs 42 and 43 of the work support, see Figs I and Ill. The feed dog 30 receives its feed movements through oscillation of the'rocker 46 by means of a link 45, which, at Aone end, has pivotal connection with the wrist pin 31, and which, at the other end, is connected to a small crank 46 at the forward end of another rotary shaft 41 below the work support I extending longitudinally of the machine parallel with the hook shaft I2. The link 45 comprises two components 48 and .49 which are telescopically interengaged as shown, the tubular component 48 having a pivotal connection at 58 with one end of a link 5I. 'I'he other end of the link 5I is :in turn'pivotally connected" ing a'xed lug 59 within the oil sump I1 and the other with a lateral, lug projection 66 on the finger, maintains said finger in contact with the end of an adjusting screw 6I. As shown, this adjusting screw 6I has threaded engagement with the lug 59 above referred to, and extends to the exterior through a bearing 62 in the front wall of the standard 3, where it is provided with a knurled finger knob 63. By turning the screw 6I it is pos;- sible to vary the feed movement of the feed dog 30 after the manner disclosed in a copending application Serial No. 673,738 filed by GeorgeSauer et al. on May 31, 1933. By reference to Fig. IV it will be observed that the feed bar 35 has a downwardly extending arm 65 which is pivotally connected at 66 to the bottom end of a vertical link 61, At the top, the link 61 engages a small crank pin 68 at the left hand end of still another longitudinal rotary shaft 69 which is parallel with the rotary shafts I2 and 41 below the work support I. the necessary up and down or lift movements are imparted to the feed dog 30. Adjacent their left hand ends, the rotary shafts 41 and 69 are respectively journaled in bushings 10 and 1I constructod like the bushing I3 for the hook shaft I 2, the bushing 10 being set into a pendant lug 112 on the work support I, while the bushing 1I is set into a separate lug 13 on said work support.

At the right hand end of the machine the shafts A By the connections just'described,

displacement through a collar 16 and the boss of a helical gear wheel 11 respectively engaging opposite ends of the bushing14. 'I'he shaft 69 is held against axial displacement in a like manner by a collar 18 and the hub of a gear wheel 19 respectively abutting the outer and inner ends of the bushing 15. The gear wheels 11 and 19 are of one to one ratio so that the feed advance and feed lift shafts 41 and 69 are driven at the same speed, while the pinion 28 which meshes with the gear wheel 19 has a diameter half that of said gear wheel so that the rotary hook shaft I2 revolves at twice the speed of the shafts 41 and 69. The gear wheel 19 on the feed lift shaft y 69 receives rotary motion from the main shaft 4 through a gear wheel 88 on the latter and an interposed idler gear 8| of larger diameter. As shown, the idler gear wheel 8I is mounted for free rotation on a shaft 82 extending crosswise of the hollow standard 3 and is held against axial shifting by thrust collars 83 and 84 secured to said shaft and engaging the opposite ends of the hub of said gear. During the operation of the machine oil is carried up from the sump I1 by the gear wheel 11 and through splash and capillarity passed to the other gears of the system within the hollow standard 3 and the communicating sump I1, the gear system being thereby selflubricating, and part of this oil finding its way into the bearing bushings I6, 14 and 15 in` a manner already understood.

Due to employment, as herein shown and described, of separate shafts of small diameter with small cranks and light associated links for imparting the feed and lift movements to the feed dog and a separate small diameter shaft for the rotary hook, provision of relatively short, selflubricating bearings affording liberal oil clearances around said shafts, and utilization of a system of rotary gears to interconnect the three shafts with each other and with the shaft from which the needle derives its movements, the machine of our invention can be operated at very much higher speeds than ordinary types of lock stitch sewing machine without liability to derangement, and without danger of heating to a point where very rapid and excessive wear would result.

Fig. VI shows a slight modification wherein the axis of the telescoping portions of the components 48a and 49a of the link 45a lies in the plane containing the wrist pin 31 and the crank pin 46, instead of being offset from such plane as is the case withvthe construction of Figs. IV and V. This modified construction necessitated shortening of the link component 48a and corresponding lengthening of the component 49a as shown, as well as downward bowing of the latter component so as to clear the shaft 69. vAll the other elements shown in Fig. VI having their counterparts in Figs. I-V, have been designated by the same reference numerals previously employed' in order to preclude the necessity of repetitive description.

Having thus described our invention, we claim:

1. In a lock stitch sewing machine, a needle; a cooperating rotary hook; a feed dog; parallel rotary shafts, one carrying the rotary hook, and two others respectively having means whereby lift and feed movements are imparted to the feed dog; .and rotary drive means interconnecting said shafts.

2. In a lock stitch sewing machine, a needle; a cooperating rotary hook; a feed dog; parallel rotary shafts, one carrying the rotary hook, and

two others respectively having cranks whereby feed and lift movements are imparted to the feed dog; and rotary drive means interconnecting said shafts.

3. In a lock stitch sewing machine, a needle; a cooperating rotary hook; a feed dog; parallel rotary shafts, one carrying the rotary hook, and two others respectively having means whereby lift and feed movements are imparted to the feed dog; and a system of gear wheels interconnecting said shafts.

4. In a lock stitch sewing machine, a needle; a cooperating rotary hook; a feed dog; parallel rotary shafts, one carrying the rotary hook, and two others respectively having means whereby lift and feed movements are imparted to the feed dog; a system of intermeshing gear wheels interconnecting said shafts; and a closed housing for said gears containing oil for their lubrication.

5. In a lock stitch sewing machine, a work support; a needle; ,a cooperating rotary hook and a feed dog beneath the Work support; parallel rotary shafts journaled beneath said work support, one carrying the rotary hook, and two others respectively having means whereby lift and feed movements are imparted to the feed dog; and rotary-drive means interconnecting said shafts.

6. In a lock stitch sewing machine, a work support, a needle; a cooperating rotary hook and a feed dog beneath the work support; parallel rotary shafts journaled beneath said work support, one carrying the rotary hook, and two others respectively having means whereby lift and feed movements are imparted to the feed dog; and a system of intermeshing gear wheels interconnecting said shafts.

'7. In a lock stitch sewing machine, a work support, a needle; a cooperating rotary hook and a feed dog beneath the work support; parallel rotary shafts journaled beneath said work support, one carrying the rotary hook, and two others respectively having means whereby lift and feed movements are imparted to the feed dog; a system of intermeshing gear wheels interconnecting said shafts; and a closed housing for the gear wheels containing oil for their lubrication.

8. In a lock stitch sewing machine, a work support; a needle; a cooperating rotary hook and a feedrdog beneath 'the work support; parallel rotary shafts journaled beneath said work support, one carrying 'the rotary hook, and two others respectively having means whereby lift and feed movements are imparted to the feed dog; intermeshing gear wheels interconnecting the feed and lift shafts in one to one ratio; and a pinion on the rotary hook shaft driven at double speed from one of said gear wheels.

9. In a lock stitch sewing machine, a needle; a rotary shaft from which @id needle receives itsmovements; a cooperating rotary hook; a feed dog; parallel rotary shafts, one carrying the rotary hook, and two others respectively having means whereby lift and feed movements are imparted to the feed dog; and rotary drive means interconnecting the hook and the feed shafts with the needle actuating shaft. Y

l0. In a lock stitch sewing machine, a needle; a rotary shaft from which said needle receives its movement; a cooperating rotary hook; a feed dog; parallel rotary shafts, one carrying the rotary hook, and two others respectively having cranks whereby feed and lift movements are imparted to the feed dog; and rotary drive means interconnecting the hook and the feed actuating shafts withthe needle actuating shaft.

l1. In a lock stitch sewing machine, a needle; a rotary shaft from which said needle receives its movements; a cooperating rotary hook; a feed` dog; parallel rotary shafts, one carrying the rof tary hook, and two others respectively having means whereby lift and feed movements are imparted to the feed dog; and a system of intermeshing gear wheels interconnecting the rotary hook and the feed shafts with the needle actuating shaft.

12. In a lock stitch sewing machine, a needle; a rotary shaft from which said needle receives its movements; a cooperating rotary hook; a feed dog; parallel rotary shafts, one carrying the rotary hook, and two others respectively having means whereby lift and feed movements are imparted to the feed dog; a system of intermeshing gear wheels interconnecting the rotary hook and the feed shafts with the needle actuating shaft; and aclosed housing for the gear wheels containing oil for their lubrication.

13. In a lock stitch sewlng'machine, a work support; a needle; a shaft above the work sup` port from which the needle is actuated; a rotary hook to cooperate with the needle, and a feed dog beneath the work support; parallel rotary shafts journaled beneath said support, one carrying the rotary hook, and two others respectively having means whereby lift and feed movements are imparted to the feed dog; and rotary drive means interconnecting the rotary hook shaft, the two feed actuating shafts and the needle actuating shaft.

14. In a lock stitch sewing machine, a work support; a needle; a shaft above the work support from which the needle is actuated; a rotary hook to cooperate with the needle, and a feed dog beneath the work support; parallel rotary shafts journaled beneath said support, one carrying the rotary hook, and two others respectively having means whereby lift and feed movements are imparted to the feed dog; and a system of intermeshing gear wheels interconnecting the rotary hook shaft, the two feed actuating shafts and the needle actuating shaft.

15. In a lock stitch sewing'machine, a work support; a needle; a shaft above the work support from which the needle is actuated; a rotary hook to cooperate with the needle, and a feed dog beneath the work support; parallel rotary shafts journaled beneath said support, one carrying the rotary hook, and two others respectively having means whereby lift and feed movements are imparted to the feed dog; a system of intermeshing gear wheels interconnecting the rotary hook shaft, the two feed-actuating shafts and the needle actuating shaft; and a closed housing for the gear wheels and containing oil for their lubrication- 16. In a lock stitch sewing machine, a work support; an overhanging arm reaching forwardly from a hollow standard at one end of the work support; a needle; a longitudinal shaft journaled in the arm from which the needle derives its movements; an oil sump projecting below the work support and communicating directly with the hollow standard; a rotary hook to cooperate with the, needle, and a feed dog beneath the work support; parallel longitudinal rotary shafts journaled beneath said work support, one carrying tary drive connections interconnecting the several shafts within the hollow standard and the A communicating oil sump.

17. In a lock stitch sewing machine, a Work support; an overhanging arm reaching forwardly from a hollow standard at one end of the work support; a needle; a longitudinal shaft journaled inthe arm from which the needle derives its movements; an oil sump projecting below the Work support and communicating directly with the hollow standard; a rotary hook to cooperate with the needle, and a feed dog beneath the work support; parallel rotary longitudinal shafts journaled beneath said work support, one carrying the rotary hook, and two others respectively having means whereby lift and feed movements are imparted to the feed dog; and a system of intermeshing self-lubricating gear wheels interconnecting the several shafts within the hollow standard and the communicating oil sump.`

18. A lock stitch sewing machine comprising a rotary hook; a feed dog; and three rotary shafts journaled adjacent their ends in spaced bearings, and all having drive means interconnecting them at one end, one of said shafts carrying therotary hook at its opposite end, and the other shafts' having, at their other ends, means for respectively imparting feed and lift movement to the feed dog.

19. A lock stitch sewing machine comprising a rotary hook; a feed dog; and three parallel rotary shafts, journaled adjacent their .ends in spaced bearings, and all having drive means interconnecting them at one end, one of said shafts carrying the rotary hook at its opposite end, and the other shafts, having at their other ends, means for respectively imparting feed and lift movements to the feed dog.

20.4 A lock stitch sewing machine comprising a rotary hook; a feed dog; three parallelshafts journaled adjacent their ends in spaced bearings, one carrying the rotary hook at one of its ends, and the other shafts having at the corresponding ends, means for respectively imparting feed and lift movements to the feed dog; and drive gears in intermeshing relation secured to the respective shafts at their opposite ends.

21. A lock stitch sewing machine comprising a work support; a needle operated from above the work support; la rotary hook cooperating with the needle beneath the work support a feed dog be- -low the work support; and three parallel rotary shafts journaled adjacent their ends in spaced bearings beneath the work support, all having drive means interconnecting them at one end, one of said shafts carrying the rotary hook at its opposite end, and the other shafts having at their other ends, means for respectively imparting feed and lift movements to the feed dog.

22. A lock stitch sewing machine comprising a .work support; a needle; a longitudinal shaft journaled adjacent its opposite-ends in spaced bearings above the work support; means at one end of said shaft for actuating the needle; a rotary hook cooperating with the needle below the f work support; a feedvdog below the work support; three parallel longitudinal rotary shafts journaled adjacent their ends in spaced bearings beneath the Work support, one of said shafts carrying the rotary hook at its forward end, and the others of the three shafts having, at the corresponding ends, means for respectively imparting feed and lift movements to the feed dog; and drive connections respectively on the other ends of said three shafts coordinated with drive means at the corresponding end of the needle-actuating shaft.'

NORMAN V. CHRISTENSEN.

HAROLD J. LE VESCONTE. 40 

